Starboard Float Inboard Half

Any time you start something new there's always a learning curve involved, which to me is really the best part of doing anything anyway. I just love picking up the tricks of the trade and due to my inherent laziness I am always trying to figure out a quicker and better way to get something done.

So, back to work laying in the foam.

Since I have some pre-fabrication work to do on the net lashing tube for both floats, I decided to start laying in the foam on the rear section of the float just aft of the raised area. This area of the float tapers and curves like a cone so I decided to use 6" (150mm) strips from start to finish. That was a great decision as that width lays down really easily and conforms very well.
On the previous half I made the strips go down at a slight angle and then across the bottom and back up the other side at nearly the same angle as I was trying to keep things in line as much as possible on both sides. This worked OK, but did cost a few edge cuts to allow the foam to sit well. I also had to spend a lot of extra time working the foam into place before inserting the screws.

On this half I have done a few things different that really helped a lot.
First, the smaller strip size really works well in these areas with tighter curves.
Second, I start my work on the side of the float that will eventually be the "top".  This side has the hard curve area where it transitions from the "top" of the float down to the "side". I measure from the top of the frame to the middle of that curve and then make a slight pencil mark on the foam strip to show where the curve should be. Once that's done, I just concentrate heat on both sides of the strip in that location and out about 12" (300mm) on either side of the pencil mark. The heating period takes maybe a minute on both sides. As the foam starts to heat up, I can push down on it near the location of bend with my fist and push the top of the foam with my chest up against the battens. The idea is the get most of the bend in place and the foam somewhat pliable before pushing it down into the framing. Now this is the fun part, once I start pushing the foam into place with one hand, I keep the heat gun on that area until I'm happy with the seated location. Then I switch the heat gun to LOW and place it on the battens in such a way that it's blowing warm air at the other end of the foam. I keep the heat gun far enough away that it doesn't cause any damage, it's just sorta "warming things up". Meanwhile, I start working the clamps in position to hold the foam nice and firmly against that big curve. Once that's good, I only need to apply a little bit of heat on the "top" side to make the foam conform to the slight bend there and then I put the gun back on LOW and aimed at the other end of the foam again while I insert all the screws on the side I just finished. Once that's done, I move to the other side and get it clamped down and secured. It doesn't take very long since there isn't as much of a curve there and the foam is already a little warmed up.
And finally, I laid the first strip vertically down the "top" side and let the other side sit where it wanted to naturally fall. This turned out to be a great decision, since the rest of the strips are falling right into place with very little coaxing.

This was done in less than three hours, so I'm down to about 20 minutes/strip.

The fit is looking really nice

This is the largest gap I have near the "big curve" not bad at all

In this picture, I'm trying to show how the near side of the foam goes down vertically (up against the raised section of the deck) and then back up the other side at a skewed "natural" angle.

Moving on to the Wingnet Support, I wanted to slightly raise the inboard section of that area in order to better line up with the beam attachment points (shown as saddle attachments in the picture below). I also wanted to have a built-in and reinforced tubing area that would not have to be installed later and would be able to stand up to the pressure of someone putting all their weight in that area. You can see in the photo how this inboard corner will be a natural area to stand and needs to be strong enough to take the weight plus support the nets.

And yes, I did run this minor modification past Ian.
His only comment was to make sure I modified the bulkhead shape to suit.

Proposed Wingnet support tube

This photo was turned upside down to show a physical representation of the idea with nearly the correct angles replicated.
The top side (with the double layer of foam) will be Pre-Fabricated (glued and wrapped in a layer of glass) before being placed into position in the float and butted up against the other piece of foam. I may also put in a second piece of foam on the angled section going "down".

Starboard Float Outboard half planking complete

Tonight I was able to complete planking on the outboard half of the starboard float.

I also had time to sweep up the shop and get things organized for starting on the inboard half.  

I did manage to get the process down to about 30 minutes per plank for the 12" (305mm) widths and about 25 minutes on the 6" (153mm) planks. That includes the time required to trim the plank edges if required and insert all the screws from the backside.

It's a time consuming process for sure, but it feels good to see progress.

I'm thinking the fairing process will be the opposite in that you still spend all day doing working but there isn't a whole lot to show for it except a layer of dust over the whole shop.

Anyway, some pics of the progress so far:

This is larger than the final product since I have a 3" (75mm) flange built in for the vacuum infusion.
But looking at this picture, I'm just now realizing that I cut the bow section flush and will need to go back and glue an extension in place to create a flange. :/

This will eventually be a really nice transition between the round float and the flat topped area.

Lots of work left to do on the foam before it's ready for laying up the fabric.
First I will sand down all these ridges to produce a smooth interior and then run a Dremel bit along the seams to open them up to receive a bead of epoxy filler. (See Below)

I did end up finding out how much pressure I could put on a piece of foam.

Moving on to another subject, I have noticed that some builders will lay down a layer of tape or some sort of plastic film between the foam planks so they don't end up causing problems with epoxy running through and sticking to the battens later on. I didn't do that, but wanted to make sure it wouldn't cause problems so I took a couple pieces of scrap foam and set them on a board with an extra large gap, then I mixed up some epoxy and Cabosil to a "cake frosting" consistency and applied it with a disposable cake decorating bag between the pieces of foam. I was hoping to get a good fill without pushing epoxy onto the mounting boards. Then I wanted to tool off the surface to produce a concave joint fill that could be back filled with a lighter (micro-balloon) second layer to ensure the joints will be air tight.  The test went really well and the colors even matched pretty closely which was a bonus I guess.

Filled gap before tooling

It's hard to make out, but the joint is tooled down to a concave surface

Not a great picture, but you can see that I was able to get about an 80% fill without touching the bottom on this extra large gap.

A pretty decent shot of the bottom side of the test piece. It looks as if the epoxy bead rises above the surface, but it doesn't.

Weekend Progress - First Foam

This weekend was spent bending foam.

It was my first hands on experience and I was really nervous that I'd be too aggressive and snap the sheets so I really took my time. The first strip took two hours!
Now that did include all the stops to pick up different tools and figure out what was needed to get the job done, but by the third strip I was getting the time down to about 40 minutes. Still a long time, but I haven't snapped a sheet yet, so that's a good thing, right?

I did find that the foam is a lot tougher than I expected and breaking a small cut-off in my hand felt much different than snapping a piece of blue or pink insulation foam. The latter will only bend a little before snapping while the corecell bends and then feels "plasticky" before breaking.

In the end, I was able to lay down nine strips this weekend for a total of 9' (2.7m). I'm hoping the pace picks up a bit, but I'd rather get them done right instead of rushing. I did notice that my last two strips are laying down better than the second and third. I think it's because I'm being more aggressive and over-bending the strips so that when I pull it back to the stringers it sits deeper into the curve.

First strip in place before trimming to size

It took forever, but in the end I got a nice fit along the battens

A view from the backside

Nine strips down - a lot more to go...

In other news, I had almost forgotten about the test I set up last week.
I was curious about the release properties of some wax I found mentioned on the "Composites Central" bulletin boards and found it to be every bit as good as they said it would be.

The wooden block I applied the wax to was not very smooth and happened to be only a primer application that was sprayed over an epoxy seal coat. I had this done last year at the paint shop to ensure the primer coat would stick to the epoxy. Anyway, since this was just a test I did a really quick job of applying the wax. In fact, I didn't even wait the 15 minutes between coats as instructed. I simply applied a coat of wax, hit it with the heat gun until I saw the haze and buffed it off with a paper towel before applying the next coat. I did that four times and then laid down a coat of epoxy and some 18oz fiberglass.

After three days of cure time (because I forgot about it) I found the test block and gently pulled at one of the fabric corners, I was delighted to have the layup just pop right off with no effort at all. So for a very easy to apply (and obviously very forgiving) product, I'll highly recommend "Grignard Mold Magic" It's a bit hard to find, but I ordered two tins from www.marineoutfitters.ca for under $42/shipped.

As for the the fabric sticking to the tube, I wasn't overly pleased with that. I did scuff the tube and clean it well before laying down the fabric, but I'm thinking I'll need to be more aggressive with the sanding grit and maybe follow that with a scuffed coat of epoxy. After that, I think we'll be good to go.

Some work in the shop today

Some work in the shop today as you can see I've graduated to stitching segments together.
A lot to learn, but I'm having fun with the camera.

Remember that "Oversized" fabric rack I made earlier? I thought it might be too big, but as it turns out, the Vacuum Film was too long and couldn't be accommodated plus I needed to add a couple more slots for the fabric on order.

Anyway, after a little bit of cleanup tomorrow and some quick sanding along the battens I'll be laying down some foam.

So another big learning curve coming up....

Modifications to the framing and a quick test

After looking over the frames and battens I just wasn't happy with the way the raised flat section of the floats were looking. I figured it might come out flatter if I replaced the battens in that area with some MDF. If it helps at all, it'll reduce the fairing work later on, but that's yet to be seen.

I also added some 3" (75mm) extensions to the edge to provide a working flange for the vacuum infusion.

Tomorrow I'm supposed to get a shipment of epoxy, but I'm still waiting on a ship date for the fabrics. This weekend I'll be picking up some additional lumber so I can rip some more battens for the flange extensions. And if all goes well, I might be able to start bending some foam.

I'm also doing a quick test to determine how well the epoxy will stick to the fiberglass tubes I purchased for the trampolines and at the same time I'll see if the release wax I bought will work as expected.

Extensions to support flange

Battens replaced with MDF to provide a flatter base.

Same thing on the other side

The front half of this block was waxed a few times to check the release properties of the wax I purchased while the rest of the fabric was wrapped around a piece of fiberglass tubing  to see how will it bonds.

Stringers installed on second float half

I uploaded a quick video showing some work on the Starboard float raised deck framing.
No audio as I haven't taken the time to figure out the GoPro Studio software yet.
 - They do provide some templates with music, but from what I can tell it's all adrenaline junkie selections. I didn't think it fit in well with a middle-aged guy walking around a wooden structure.

**UPDATE**
YouTube makes it easy to insert some music and add some comments. I made a few quick edits and it's a bit better now. The learning curve continues!

Anyway, I did get the stringers (battens) installed in the second float half. I think it came out better than the first half, but I was forced to use pieces and scraps toward the end due to some poor quality (knotty) wood being used for the initial cuts.

Note to self:
Don't rely on the delivery guys to pick clear lumber.

Later today my son and I will be relocating the left over stack of MDF and cleaning the shop.

In the middle of this float you can just make out the raised deck section to match the other float.